Get Tons of Points Start a two-player game and proceed to strike out every batter on each side until the bottom of the ninth inning.
When you've got 2 outs at the bottom of the ninth, walk the next 4 hitters to earn enough points to buy 100 card packs, which should get you almost every card. If not, repeat and get yourself more card packs.
NOTE This doesn't include special cards earned in Scenario Mode.
More All Star Baseball 2004 cheats at: Cheat Masters